Unit 3 The internet Section Ⅳ　Discovering Useful Structures 课件（共45张）+讲义

Section Ⅳ　Discovering Useful Structures———现在完成时的被动语态 一、定义 现在完成时的被动语态表示动作已经完成,强调对现在造成的影响或结果,而且主语和谓语动词之间是被动的关系。 二、结构 肯定式 主语+have/has been done... 否定式 主语+have/has not been done... 一般疑问式 Have/Has+主语+been done... 特殊疑问式 特殊疑问词+have/has+主语+been done... 三、用法 [先感知] ①Much has been written about the wonders of the World Wide Web.(人教必二U3) ②I guess you have been asked about the title of your book before.(外研必三U3) ③How long has this film been shown ④You shouldn’t leave school before your homework has been finished. [会发现]　 ①②③④句都使用了现在完成时的被动语态。①②④句为现在完成时的被动语态的肯定式;③句为特殊疑问式。 [明规则]　 1.现在完成时的被动语态同它的主动语态一样,强调过去的动作对现在造成的影响或结果,通常与already、yet、just、never、recently等副词连用。 2.表示一个被动的动作或状态开始于过去,持续到现在,并可能持续下去,常与for或since引导的时间状语连用,或用于“How long... ”句型中。 3.用在时间或条件状语从句中,表示将来某时已完成的动作,即用现在完成时的被动语态代替将来完成时的被动语态。 [联想发散] 常与现在完成时连用的时间状语: already　　　　　已经 yet 已经 recently/lately 最近 since then 从那时起 ever since 自那以来 ever 曾经 so far 迄今为止 for a long time 很长一段时间 by now 到现在为止 in recent years 在最近几年里 in/during/over the past/last years 在过去的几年里 [再运用]　 (1)用现在完成时的被动语态改写句子 ①Jack’s boss has always praised him for his devotion to work. →Jack has always been praised by his boss for his devotion to work. ②They have found a good place to build a temple in the village. →A good place has been found by them to build a temple in the village. ③We haven’t yet decided how to solve that difficult technological problem. →How to solve that difficult technological problem hasn’t been decided by us yet. (2)补全句子 ④I will go home when my homework has been finished. 当我的家庭作业完成时,我就回家。 ⑤This tool has been used for over one thousand years. 这个工具已经被使用了1 000多年了。 四、注意事项 1.短语动词的被动语态 英语中的被动语态由“助动词be+及物动词的过去分词”构成。有些短语动词在意义上相当于及物动词,因此也可构成被动语态。短语动词被看成一个整体,是固定词组,所以构成被动语态时不可分开。其被动语态构成方法与普通的及物动词的被动语态的构成方法相同。 [先感知] ①He has been operated on by the best surgeon. ②These problems have been seriously thought over. ③Women have been looked down upon in the past few years. ④The children have been taken good care of. [会发现]　 ①②③④句中的被动语态都是由短语动词构成的。 [明规则]　 对于短语动词的被动语态,要注意:短语动词是一个整体,不可丢掉后面的介词或副词。 [再运用]　将下列句子改成被动句 ①Grandma has taken care of my sister for 3 years. →My sister has been taken care of by Grandma for 3 years. ②Tom has sold out all the books. →All the books have been sold out by Tom. 2.带有双宾语的句子变为被动结构 [先感知] The company has given him a chance to work abroad recently. →He ... ...